| Nowadays, global environmental changes and regional response are followed research in science areas. "The present is the key to the past". Past global changes is the core of Global Changes Research Program, which main aims is to predict the future of regional and global trends of climate and environmental evolutions.The study area Wangtianping Section is the central of the Three Gorges Reservoir Area,which is located in the eastern edge of the Sichuan Basin, it is a good carrier Which is scattered in different geomorphological units of loess-like sediments to study the paleoenvironmental evolution.So it is of great significance to understand Quaternary paleoenvironmental evolution of regional differences.Based on detailed rock magnetic analyses of the sediment overlying carbonate rock, including magnetic susceptibility (χ),isothermal remanent magnetization(IRM),thermomagnetic curve(T-c) and anisotropy of magnetic susceptibility (AMS),heavy metals and organic matter analysis, this study discussed the relationship between the magnetic characteristics and sediment environment in Wushan County. The main conclusions are as follows:(1)The magnetic parameters of magnetic susceptibility (χ),saturation remanence susceptibility (SIRM),hard remanent magnetic susceptibility (HIRM),thermomagnetic curve(T-c) and Hysteresis loop indicates that magnetic mineralogy of the sediment is dominated by maghemite and paramagnetic mineral with a amount of hematite and minor of magnetite.(2) The Magnetic parameters of frequency dependent susceptibility (χfd%),χarm and the ratioχARM/SIRM,SIRM/χshows that the main magnetic grain sizes of Wangtianping section are single domain(SD)and stable single domain (SSD), and contains a certain amount of super-paramagnetic particles(SP).(3) The magnetic susceptibility(x) of Wangtianping section has obvious vertical fluctuations, The surface to 40cm depth, magnetic susceptibility(x) is low levels, modest, and in the formation of 40cm at valley value; In the upper 40～150cm depth,χincreases with the depth, and reached the maximum at 150cm; 150～200cm depth in the lower part,x decreasing again in the 200 cm trough the formation of small; 200～310cm depth,χin the 220cm, after the formation of a small peak, and then down again on the decrease. Overall, magnetic susceptibility(x) of section is low level,χchanges in the range of 7.93×10-8～19.73×10-8m3/kg, average of 15.66×10-8m3/kg, less than the Northwest Luochuan loess and Xiashu loess.It is found that the magnetic susceptibility shows a closer relationship with stable single domain (SSD) and super-paramagnetic particles(SP).Thus, the level of magnetic susceptibility(x)values reflect the intensity of pedogenesis and it is suggested that magnetic susceptibility(x) can be considered an indicator for the paleoenvironment changes.(4)The magnetic properties of anisotropy of magnetic susceptibility (AMS)P,F,L,and q are remarkably different from those of hydraulic deposit,We put forward that the sediment overlying carbonate rock formed as eolian deposit.(5) Low levels organic matter of Wangtianping section indicate the formation of during the dry and cold climate and not conducive to biological growth. At the same time, the period's climatic environment which forms of the section may be conducive to the detriment of the decomposition of organic matter and reduce the levels of organic matter.The organic matter content and magnetic susceptibility showed a positive correlation,but a low correlation coefficient (0.051evel), its concentration level can not causes the main reason for the fluctuations of magnetic susceptibility.(6) It is a high correlation between Heavy metals Zn,As,Cu,Ni,Fe,Cu,Co and Mn reflects there is a similar geochmical behavior on source,migration and enrichment. After calculating the correlation coefficient between the heavy metal contents and magnetic parameters, it is found that the contents ofχ,χARM,χfd SIRM/χand Fe,Co,As,Zn,As had high correlation. According to the remarkable correlation of the heavy metal contents and magnetic parameters, the diagnostic models were set up:Fe=5.96χ-1.61χfd-0.013χARM-0.60; Co=0.774χ-0.072χARM+0.007χfd+2.886; As=0.557χ-0.044/SIRM/χ+13.028; Zn=5.936χ+0.119χARM+2.012χfd+2.886; Ni=3.751χ-0.017χARM-0.736χfd-5.738.
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